Device for decreasing concentration of hydrogen exhausted from fuel cell

ABSTRACT

A device for decreasing a concentration of hydrogen exhausted from a fuel cell through an exhaust line includes: a first housing connected to the exhaust line and having an exhaust gas moving path and an air inlet formed therein; a pumping part installed in the first housing and sucking air through the air inlet; a second housing coupled to the first housing and having an air diluting part and a diluted gas moving path formed therein, the air diluting part being connected to the exhaust gas moving path and the diluted gas moving path being connected to the air diluting part; and a nozzle member spraying the air introduced into the air inlet to the air diluting part while being rotated.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of non-provisional U.S.patent application Ser. No. 15/377,900, filed on Dec. 13, 2016, whichclaims priority to and the benefit of Korean Patent Application No.10-2016-0130654, filed on Oct. 10, 2016, the entire contents of whichare incorporated herein by reference.

FIELD

The present disclosure relates to a device for decreasing aconcentration of hydrogen exhausted from a fuel cell capable ofdecreasing a concentration of hydrogen in exhaust gas.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

Generally, a fuel cell system is a kind of power generation systemgenerating electric energy by supplying air and hydrogen to fuel cellsand generating an electrochemical reaction between the hydrogen andoxygen in the fuel cells. For example, the fuel cell system has beenused to drive a driving source such an electric motor in a vehicle, aship, a train, an airplane, and the like.

The fuel cell system includes a stack in which the fuel cells arestacked, a hydrogen supplying device supplying hydrogen to anodes of thefuel cells, an air supplying device supplying air to cathodes of thefuel cells, and a heat/water managing device removing heat and water,which are reaction products of the fuel cells, and controlling a drivingtemperature of the stack.

In a polymer electrolyte membrane fuel cell, appropriate moisture isrequired in order for an ion-exchange membrane of a membrane-electrodeassembly (MEA) to perform a smooth role. To this end, the fuel cellsystem has used a humidifying device humidifying reaction gas suppliedto the stack.

The humidifying device humidifies the air supplied from the airsupplying device using moisture in hot and humid air exhausted from thecathodes of the fuel cells, and supplies the humidified air to thecathodes of the fuel cells.

In addition, the fuel cell system includes a hydrogen re-circulatingdevice mixing hydrogen exhausted from the anodes of the fuel cells andthe hydrogen supplied from the hydrogen supplying device with each otherand again supplying the mixed hydrogen to the anodes.

Meanwhile, impurities such as nitrogen, vapor, and the like, areaccumulated in the anodes of the fuel cells during driving the fuel cellsystem, such that a concentration of hydrogen becomes low, and in thecase in which the concentration of hydrogen becomes excessively low, aphenomenon such as separation of the cell, or the like, may occur in thefuel cell stack.

In order to solve this problem, in the fuel cell system, theconcentration of hydrogen in the anodes has been managed at apredetermined level or more by periodically opening purge valves at thetime of initial start-up and driving of the fuel cell system andexhausting the impurities together with the hydrogen from the anodes.

Here, when the anodes are purged by opening the purge valves, thehydrogen is exhausted together with the impurities from the anodes, andthis purge gas is introduced together with the air exhausted from thecathodes into the humidifying device.

In this case, the vapor in the impurities is used as a humidifyingsource of reaction gas required for an electrochemical reaction of thefuel cells in the humidifying device, and gas such as the hydrogen, thenitrogen, and the like, is exhausted together with the air to theatmosphere through an exhaust system.

Therefore, in the hydrogen purge method as described above, the hydrogenexhausted from the anodes is mixed with the air exhausted from thecathodes, and is then exhausted into the atmosphere through the exhaustsystem, thereby promoting an air dilution effect of a concentration ofpurge hydrogen.

Furthermore, at the time of initial start-up and stop of the fuel cellsystem or in an idle condition of a fuel cell vehicle using the fuelcell system (for example, an idle stop and go (ISG) condition of thefuel cell vehicle), a significant amount of hydrogen crossed over fromthe anodes of the fuel cells to the cathodes of the fuel cells through amembrane is exhausted.

This hydrogen is exhausted together with the air from the cathodes ofthe fuel cell to the humidifying device, is diluted by the air in thehumidifying device, and is exhausted into the atmosphere through theexhaust system in a state in which a concentration thereof is decreased.

However, in the related art, the exhausted hydrogen is mixed with theair exhausted from the cathodes in the humidifying device depending onthe driving condition of the fuel cell system as described above topartially decrease the concentration of hydrogen, but it is difficult toimplement a sufficient mixing effect between the hydrogen and the air,such that the concentration of hydrogen is not sufficiently decreased.

Therefore, in the related art, the concentration of hydrogen exhaustedfrom the fuel cell system is not effectively decreased, and a conditionin which hydrogen that is not diluted may be exhausted is sufficientlypresent depending on a driving condition of the fuel cell system, suchthat a risk of fire and explosion may be caused by a concentration ofexhausted hydrogen exceeding a set range.

In order to prevent the risk of the fire and the explosion, a method forexhausting the hydrogen into the air through the exhaust system in astate in which the concentration of hydrogen is decreased to apredetermined level or less is used in the fuel cell system.

Recently, in order to prevent the risk of the fire and the explosion bythe hydrogen exhausted from the fuel cell, the concentration of hydrogenexhausted into the atmosphere through the exhaust system of the fuelcell system has been restricted to be less than at most 8% and be lessthan 4% on average for three seconds in related regulations of Korea andglobal technical regulations (GTR).

The disclosure of this section is to provide background of theinvention. Applicant notes that this section may contain informationavailable before this application. However, by providing this section,Applicant does not admit that any information contained in this sectionconstitutes prior art.

SUMMARY

An embodiment of the present invention provides a device for decreasinga concentration of hydrogen exhausted from a fuel cell, configured in anexhaust system of a fuel cell system exhausting exhaust gas containinghydrogen and air exhausted from the fuel cell into the atmospherethrough an exhaust line, including: a first housing connected to theexhaust line and having an exhaust gas moving path and an air inletformed therein; a pumping part installed in the first housing andsucking air through the air inlet; a second housing coupled to the firsthousing and having an air diluting part and a diluted gas moving pathformed therein, the air diluting part being connected to the exhaust gasmoving path and the diluted gas moving path being connected to the airdiluting part; a motor part installed in the second housing so as to beconnected to the pumping part; and a nozzle member installed at a shaftof the motor part between the motor part and the pumping part, andspraying the air introduced into the air inlet to the air diluting partwhile being rotated by the shaft.

On the basis of the case in which the exhaust gas is exhausted from afront to a rear through the exhaust line, the device for decreasing aconcentration of hydrogen exhausted from a fuel cell may be mounted inthe course of the exhaust line at a rear end portion of the exhaustline.

An exhaust gas introduction pipe may be coupled to a front end of thefirst housing.

An exhaust gas introduction pipe may be connected to a front connectionend in the course of the exhaust line.

A diluted gas exhaust pipe may be coupled to a rear end of the secondhousing.

A diluted gas exhaust pipe may be connected to a rear connection end inthe course of the exhaust line.

The first housing may include: a first body having a cylindrical shapeof which a front end and a rear end are opened; and a first channelforming member connected to an inner peripheral surface of the firstbody through first connection ribs having a radial shape and forming theexhaust gas moving path between the first channel forming member and theinner peripheral surface of the first body.

In the first channel forming member, a first gas inducing surface havinga conical shape may be formed at a front end of the first channelforming member, and a first mounting groove in which the pumping part ismounted may be formed at a rear end of the first channel forming member.

The air inlet may penetrate through the first body and the firstconnection ribs and be connected to the first mounting groove.

The second housing may include: a second body coupled to a rear end ofthe first housing and having a cylindrical shape of which a front endand a rear end are opened; and a second channel forming member connectedto an inner peripheral surface of the second body through secondconnection ribs having a radial shape and forming the air diluting partand the diluted gas moving path between the second channel formingmember and the inner peripheral surface of the second body.

The air diluting part may form a mixing zone connected to the exhaustgas moving path of the first housing.

A mixing protrusion for partitioning the mixing zone may be formed at afront end of the second channel forming member so as to protrude from anouter peripheral edge of the second channel forming member toward thefirst housing.

The diluted gas moving path may be formed between a rear end of thesecond channel forming member and the second body.

A second gas inducing surface having a conical shape may be formed atthe rear end of the second channel forming member.

A second mounting groove in which the motor part is mounted may beformed at the front end of the second channel forming member.

The second housing may further include: coolant moving grooves formed inthe second connection ribs and connected to the second mounting groove;a coolant inlet formed in the second body and penetrating through andconnected to the coolant moving groove of any one of the secondconnection ribs; and a coolant outlet formed in the second body andpenetrating through and connected to the coolant moving groove of theother of the second connection ribs.

The nozzle member may include a nozzle body having a disk shape havingan outer ring part formed at an edge portion thereof.

In the nozzle member, a spraying groove may be formed at an inner sideof the outer ring part, and a plurality of nozzle holes penetratingthrough the spraying groove may be formed along the spraying groove.

In the nozzle member, the nozzle member may be formed in an impellertype in which a plurality of impeller wings having a curved surface aredisposed between first and second disks and an air introduction hole isformed in any one of the first and second disks.

The air diluting part may be connected to a front end of the exhaust gasmoving path through a bypass pipeline.

A first connection hole connected to the air diluting part may be formedin the first housing.

A second connection hole connected to the first connection hole throughthe bypass pipeline may be formed in the exhaust gas introduction pipe.

Another embodiment of the present invention provides a device fordecreasing a concentration of hydrogen exhausted from a fuel cell,configured in an exhaust system of a fuel cell system exhausting exhaustgas containing hydrogen and air exhausted from the fuel cell into theatmosphere through an exhaust line, including: a first housing connectedto the exhaust line and having an exhaust gas moving path and an airinlet formed therein; a pumping part installed in the first housing andsucking air through the air inlet; a second housing coupled to the firsthousing and having an air diluting part and a diluted gas moving pathformed therein, the air diluting part being connected to the exhaust gasmoving path and the diluted gas moving path being connected to the airdiluting part; a motor part installed in the second housing so as to beconnected to the pumping part; a nozzle member installed at a shaft ofthe motor part between the motor part and the pumping part, and sprayingthe air introduced into the air inlet to the air diluting part whilebeing rotated by the shaft; and a catalyst diluting part disposed in thediluted gas moving path of the second housing and diluting hydrogen indiluted gas in which a concentration of hydrogen is diluted by air inthe air diluting part by a catalyst reaction.

A catalyst may be deposited on an inner wall surface of the diluted gasmoving path in the second housing.

A catalyst may have a plurality of lattice holes formed to move thediluted gas, and be buried in the diluted gas moving path in the secondhousing.

The lattice holes may be formed so that cross-sectional areas thereofgradually become small in a moving direction of the diluted gas.

In the second housing, a coolant moving path moving a coolant in orderto cool the motor part may be formed. In the second housing, a coolantforcible exhaust hole connecting the coolant moving path and the dilutedgas moving path to each other may be formed. In the second housing, acap formed of a polymer material destroyed at a set temperature may beinstalled in the coolant forcible exhaust hole.

Yet another embodiment of the present invention provides a device fordecreasing a concentration of hydrogen exhausted from a fuel cell,configured in an exhaust system of a fuel cell system exhausting exhaustgas containing hydrogen and air exhausted from a humidifier into theatmosphere through an exhaust line, including: a first housing connectedto the exhaust line and having an exhaust gas moving path and an airinlet formed therein; a second housing coupled to the first housing andhaving an air diluting part and a diluted gas moving path formedtherein, the air diluting part being connected to the exhaust gas movingpath and the diluted gas moving path being connected to the air dilutingpart; a motor part installed in the second housing; and a nozzle memberinstalled at a shaft of the motor part, and spraying the air introducedinto the air inlet to the air diluting part while being rotated by theshaft.

The air inlet may be connected to a breathing hole of an air compressorfor supplying the air to the humidifier through a connection line.

In embodiments of the present invention, hydrogen in exhaust gasexhausted into the atmosphere through an exhaust system of a fuel cellsystem is diluted by external air and a catalyst, and a concentration ofexhaust hydrogen is effectively decreased, thereby making it possible tosatisfy fuel cell vehicle exhaust hydrogen restriction relatedregulations of Korea and global technical regulations (GTR) and secure acompetitive advantage in terms of a decrease in hydrogen exhausted froma fuel cell vehicle.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

Since the accompanying drawings are provided only to describeembodiments of the present invention, it is not to be interpreted thatthe spirit of the present invention is limited to the accompanyingdrawings.

FIG. 1 is a block diagram schematically showing an example of a fuelcell system to which an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a device for decreasing aconcentration of hydrogen exhausted from a fuel cell according to anembodiment of the present invention.

FIG. 3 is a partially cut-away perspective view of the device shown inFIG. 2.

FIG. 4 is another partially cut-away perspective view of the deviceshown in FIG. 2.

FIG. 5 is a cross-sectional view of the device shown in FIG. 2.

FIG. 6 is another cross-sectional view of the device shown in FIG. 2.

FIG. 7 is a view showing a nozzle member used in the device fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to an embodiment of the present invention.

FIG. 8 is a view for describing an operation of the device fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to an embodiment of the present invention.

FIG. 9 is a view showing a modified example of the nozzle member used inthe device for decreasing a concentration of hydrogen exhausted from afuel cell according to an embodiment of the present invention.

FIG. 10 is a view showing a modified example of the device fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to an embodiment of the present invention.

FIG. 11 is a view showing a device for decreasing a concentration ofhydrogen exhausted from a fuel cell according to another embodiment ofthe present invention.

FIG. 12 is a view showing a modified example of the device fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to another embodiment of the present invention.

FIGS. 13A and 13B are views showing a catalyst structure used in amodified example of the device for decreasing a concentration ofhydrogen exhausted from a fuel cell according to another embodiment ofthe present invention.

FIG. 14 is a view showing a device for decreasing a concentration ofhydrogen exhausted from a fuel cell according to yet another embodimentof the present invention.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

Hereinafter, embodiments of the present invention will be described morefully with reference to the accompanying drawings so as to be easilypracticed by those skilled in the art to which the present inventionpertains. As those skilled in the art would realize, the describedembodiments may be modified in various different ways, all withoutdeparting from the spirit or scope of the present invention.

A description for contents that are not associated with the presentinvention will be omitted in order to clearly describe the presentinvention, and like reference numerals designate like elementsthroughout the specification.

Since sizes and thicknesses of the respective components werearbitrarily shown in the accompanying drawings for convenience ofexplanation, the present invention is not limited to contents shown inthe accompanying drawings. In addition, thicknesses were exaggerated inorder to obviously represent several portions and regions.

In addition, in the following description, the terms ‘first’, ‘second’,and the like, will be used to distinguish components having the sameconfiguration from each other, and will not be necessarily limited to asequence thereof.

Throughout the present specification, unless explicitly described to thecontrary, the word “comprise” and variations such as “comprises” or“comprising”, will be understood to imply the inclusion of statedelements but not the exclusion of any other elements.

In addition, the terms “˜unit”, “˜means”, “˜part”, “member”, and thelike, described in the specification mean units of a comprehensiveconfiguration for performing at least one function and operation.

FIG. 1 is a block diagram schematically showing an example of a fuelcell system to which an embodiment of the present invention is applied.

Referring to FIG. 1, the fuel cell system 1 to which an embodiment ofthe present invention is applied is a power generation system generatingelectrical energy by an electrochemical reaction between a fuel and anoxidizing agent, and may be configured in, for example, a fuel cellvehicle driving an electrical motor by the electric energy.

In an embodiment of the present invention, the fuel used in the fuelcell system 1 may be defined as hydrogen gas (hereinafter, referred toas “hydrogen” for convenience), and the oxidizing agent used in the fuelcell system 1 may be defined as air.

The fuel cell system 1 basically includes a fuel cell stack 2, an airsupplying unit 3, a hydrogen supplying unit 4, a humidifier 5, ahydrogen re-circulating unit 6, and a heat/water managing unit 7.

The fuel cell stack 2 is an electricity generation assembly of fuelcells 2 c each including a membrane, a cathode 2 a, and an anode 2 b.The fuel cells 2 c may receive hydrogen at the anodes 2 b thereof andreceive air at the cathodes 2 a thereof to generate electric energy byan electrochemical reaction between the hydrogen and oxygen.

The air supplying unit 3 is driven by receiving power applied thereto,and supplies air in the atmosphere to the cathodes 2 a of the fuel cells2 c. The air supplying unit 3 may include an air compressor or an airblower. The hydrogen supplying unit 4 may include a hydrogen tankcompressing and storing the hydrogen therein and supplying the hydrogento the anodes 2 b of the fuel cells 2 c.

The humidifier 5 may include a membrane-humidifying device humidifyingthe air supplied from the air supplying unit 3 using air exhausted fromthe cathodes 2 a of the fuel cells 2 c and containing moisture andsupplying the humidified air to the cathodes 2 a.

The hydrogen re-circulating unit 6 is to re-circulate hydrogen exhaustedfrom the anodes 2 b of the fuel cells 2 c to the anodes 2 b. Thehydrogen re-circulating unit 6 may mix the hydrogen exhausted from theanodes 2 b and the hydrogen supplied from the hydrogen supplying unit 4with each other through an ejector, or the like, and supply the mixedhydrogen to the anodes 2 b.

The heat/water managing unit 7 is to remove heat and water, which arebyproducts generated at the time of the electrochemical reaction of thefuel cells 2 c, and control a driving temperature of the fuel cell stack2.

Since various components of the fuel cell system 1 described above arewell-known to a person of an ordinary skilled in the art, a detaileddescription therefor will be omitted in the present specification.

Meanwhile, in the case in which the fuel cell system 1 as describedabove is used in a fuel cell vehicle, the fuel cell system 1 exhaustshydrogen due to cross-over together with air from the cathodes 2 a ofthe fuel cells 2 c and exhausts purge hydrogen from the anodes 2 b ofthe fuel cells 2 c, when the vehicle is started.

In addition, the fuel cell system 1 exhausts only purge hydrogen fromthe anodes 2 b of the fuel cells 2 c when the vehicle is driven, andexhausts hydrogen due to cross-over together with air from the cathodes2 a of the fuel cells 2 c when the vehicle is stopped or is in an idlecondition (for example, an idle stop and go (ISG) condition).

Here, the cross-over hydrogen may be defined as hydrogen crossed over tothe cathodes 2 a through membranes by residual pressure of hydrogenpresent in the anodes 2 b of the fuel cells 2 c when driving of the fuelcell system 1 is stopped.

In addition, the purge hydrogen may be defined as hydrogen exhaustedtogether with impurities from the anodes 2 b by an operation of a purgevalve 8 in order to remove the impurities such as nitrogen, vapor, andthe like, accumulated in the anodes 2 b of the fuel cells 2 c duringdriving the fuel cell system 1.

As described above, hydrogen containing the hydrogen or the airexhausted from the fuel cells 2 c is supplied to the humidifier 5 by wayof example, and is exhausted together with air from the humidifier 5.The hydrogen is diluted by the air, and is exhausted in a state in whicha concentration thereof is partially decreased.

In embodiments, when the vehicle is started, is driven, and is stoppedor is in the idle condition, the hydrogen exhausted from the fuel cells2 c is introduced together with the air exhausted from the fuel cells 2c into the humidifier 5, and may be exhausted in a state in which aconcentration thereof is partially decreased by the air.

The fuel cell system 1 includes an exhaust system 9 for exhausting thegas (which is gas containing the hydrogen and the air and willhereinafter be called “exhaust gas”) exhausted through the humidifier 5into the atmosphere. Here, the exhaust gas includes water and vapor, inaddition to the hydrogen.

The exhaust system 9 described above includes an exhaust line 9 afixedly installed from the front to the rear in a lower structure of thevehicle. The exhaust line 9 a moves the exhaust gas from the front ofthe vehicle to the rear of the vehicle, and exhausts the exhaust gasinto the atmosphere.

Further, the exhaust line 9 a is an exhaust pipe moving the exhaust gas,and various components such as a muffler decreasing exhaust noise, asensor sensing a concentration of hydrogen, and the like, may beinstalled in the course of the exhaust line 9 a.

Meanwhile, when the vehicle is started and is stopped or is in the idlecondition, a low flow rate of exhaust gas is exhausted through theexhaust line 9 a. The vehicle condition as described above is a low flowrate condition and a low pressure condition of the exhaust gas. In thiscase, the exhaust gas includes a relatively high concentration ofhydrogen.

In addition, when the vehicle is driven, a high flow rate of exhaust gasis exhausted through the exhaust line 9 a. The vehicle condition asdescribed above is a high flow rate condition and a high pressurecondition of the exhaust gas. In this case, the exhaust gas includes arelatively low concentration of hydrogen.

Here, the low flow rate/low pressure condition and the high flowrate/high pressure condition of the exhaust gas may be determined bypower consumed in the air compressor or the air blower.

In an embodiment of the present invention, since the low flow rate/lowpressure condition and the high flow rate/high pressure conditiondescribed above are clearly distinguished from each other depending on astate of the vehicle (a state in which the vehicle is started, a statein which the vehicle is driven, a state in which the vehicle is stopped,or a state in which the vehicle is in the idle condition), the low flowrate/low pressure condition and the high flow rate/high pressurecondition are not limited to any specific numerical ranges.

A device 100 for decreasing a concentration of hydrogen exhausted from afuel cell according to an embodiment of the present invention may beconfigured on the exhaust line 9 a of the exhaust system 9. The device100 for diluting hydrogen in the exhaust gas or decreasing aconcentration of hydrogen exhausted from a fuel cell according to anembodiment of the present invention has a structure in which it mayeffectively decrease a concentration of hydrogen in the exhaust gasexhausted into the atmosphere through the exhaust system 9 in thevarious vehicle conditions as described above and satisfy fuel cellvehicle exhaust hydrogen restriction related regulations of Korea andglobal technical regulations (GTR).

In embodiments, in an embodiment of the present invention, the device100 for decreasing a concentration of hydrogen exhausted from a fuelcell that may effectively decrease the concentration of hydrogen bydiluting hydrogen in the exhaust gas exhausted through the exhaust line9 a by external air is provided.

FIG. 2 is a perspective view showing a device for decreasing aconcentration of hydrogen exhausted from a fuel cell according to anembodiment of the present invention. FIG. 3 is a partially cut-awayperspective view of the device shown in FIG. 2, and FIG. 4 is anotherpartially cut-away perspective view of the device shown in FIG. 2.

Referring to FIGS. 2 to 4, the device 100 for decreasing a concentrationof hydrogen exhausted from a fuel cell according to an embodiment of thepresent invention basically includes a first housing 10, a pumping part30, a second housing 40, a motor part 70, and a nozzle member 90. Thefirst housing 10 and the second housing 40 are coupled to each other toform a housing assembly.

Before describing the respective components as described above, thedevice 100 for decreasing a concentration of hydrogen exhausted from afuel cell according to an embodiment of the present invention may bemounted in the course of the exhaust line 9 a at a rear end portion ofthe exhaust line 9 a.

The device 100 for decreasing a concentration of hydrogen exhausted froma fuel cell according to an embodiment of the present invention ismounted at the rear end portion of the exhaust line 9 a, as describedabove, in order to prevent condensate from being frozen in the course ofthe exhaust line 9 a in winter by easily exhausting the condensategenerated by condensation of moisture in the exhaust gas moving alongthe exhaust line 9 a.

In addition, the device 100 for decreasing a concentration of hydrogenexhausted from a fuel cell according to an embodiment of the presentinvention is mounted at the rear end portion of the exhaust line 9 a inorder to maximize dilution performance between the hydrogen in theexhaust gas exhausted through the exhaust line 9 a and external air.

Here, a phrase “the course of the exhaust line 9 a” may be defined as azone between one portion 9 b of a rear end portion in the entire exhaustline 9 a and the other portion 9 c except for the one portion 9 b. Theone portion 9 b and the other portion 9 c are fixedly installed to alower structure of the vehicle.

The device 100 for decreasing a concentration of hydrogen exhausted froma fuel cell according to an embodiment of the present invention ismounted in the zone between the one portion 9 b and the other portion 9c of the exhaust line 9 a and connects the one portion 9 b and the otherportion 9 c to each other.

Hereinafter, a connection end of the other portion 9 c connected to thedevice 100 for decreasing a concentration of hydrogen exhausted from afuel cell in the course of the exhaust line 9 a will be referred to as afront connection end 9 d. In addition, a connection end of the oneportion 9 b connected to the device 100 for decreasing a concentrationof hydrogen exhausted from a fuel cell in the course of the exhaust line9 a will be referred to as a rear connection end 9 e.

Further, the term “end” described above may be defined as an end of anyone side or be defined as a certain portion (an end portion) includingthe end. In an embodiment of the present invention, the term “end” willbe defined as the latter.

Meanwhile, the device 100 for decreasing a concentration of hydrogenexhausted from a fuel cell according to an embodiment of the presentinvention is not necessarily limited to being mounted in the course ofthe exhaust line 9 a at the rear end portion of the exhaust line 9 a asdescribed above, but may also be mounted at a rear end (a rear terminal)of the exhaust line 9 a.

However, an example in which the device 100 for decreasing aconcentration of hydrogen exhausted from a fuel cell according to anembodiment of the present invention is mounted in the course of theexhaust line 9 a at the rear end portion of the exhaust line 9 a willhereinafter be described.

FIG. 5 is a cross-sectional view of the device shown in FIG. 2, and FIG.6 is another cross-sectional view of the device shown in FIG. 2.Hereinafter, the following components will be described in detail withreference to FIGS. 5 and 6 together with the drawings provided above.

In an embodiment of the present invention, the first housing 10, whichis connected to the front connection end 9 d of the exhaust line 9 a, isconnected to the front connection end 9 d through an exhaust gasintroduction pipe 20. The exhaust gas introduction pipe 20 into whichthe exhaust gas exhausted to the exhaust line 9 a is introduced iscoupled to a front end of the first housing 10, and is connected to thefront connection end 9 d.

The first housing 10 includes a first body 11 and a first channelforming member 13. The first body 11 has a cylindrical shape of which afront end and a rear end (both ends) are opened, and is connected to theexhaust gas introduction pipe 20 having an inlet.

The first channel forming member 13 is disposed in the first body 11.The first channel forming member 13 forms an exhaust gas moving path 15between an outer surface thereof and an inner peripheral surface of thefirst body 11. The exhaust gas moving path 15 is a channel through whichthe exhaust bas introduced from the exhaust line 9 a into the exhaustgas introduction pipe 20 moves rearward.

The first channel forming member 13 is connected to the inner peripheralsurface of the first body 11 through first connection ribs 17 having aradial shape. The number of first connection ribs 17 is two or more, forexample, four, and the first connection ribs 17 are disposed to bespaced apart from each other by a predetermined interval in an innerperipheral direction of the first body 11.

The first connection ribs 17 integrally connect an outer surface of thefirst channel forming member 13 and the inner peripheral surface of thefirst body 11 to each other. Therefore, the exhaust gas moving path 15is formed between the first connection ribs 17, between the outersurface of the first channel forming member 13 and the inner peripheralsurface of the first body 11.

In addition, the first channel forming member 13 has a first gasinducing surface 19 formed at a front end thereof, the first gasinducing surface 19 having a conical shape such as a taper shapeprotruding forward. The first gas inducing surface or flow guide surface19 serves to induce or guide the exhaust gas introduced from the exhaustline 9 a into the exhaust gas introduction pipe 20 to the exhaust gasmoving path 15 of the first housing 10 located in the peripheral regionin the inside space of the housing assembly.

In addition, the first channel forming member 13 has a first mountinggroove 21 formed at a rear end thereof. The first mounting groove 21 isformed forward at the rear end of the first channel forming member 13.The first mounting groove 21 is provided as an accommodating groove inwhich a pumping part 30 to be described below is mounted.

Further, the first housing 10 has air inlets 23 formed therein in orderto introduce external air into the first mounting groove 21. The numberof air inlets 23 formed in the first housing 10 may be one or more. Theair inlet 23 has a hole shape penetrating through the first body 11 andthe first connection rib 17 and connected to the first mounting groove21.

The pumping part 30 as described above, which is a vacuum pumping meanssucking the external air through the air inlet 23, includes, forexample, a rotary vane as well-known to a person of an ordinary skilledin the art. The pumping part 30 is installed in the first mountinggroove 21 of the first channel forming member 13. The pumping part 30 isrotatably installed in the first mounting groove 21.

In an embodiment of the present invention, the second housing 40, whichis coupled to a rear end of the first housing 10, is connected to therear connection end 9 e of the exhaust line 9 a. The second housing 40is connected to the rear connection end 9 e through a diluted gasexhaust pipe 50. The diluted gas exhaust pipe 50, which is to exhaustdiluted gas in which a concentration of hydrogen in the exhaust gas isdiluted by the external air at the second housing 40 and/or a coupledportion between the first and second housings 10 and 40, is coupled to arear end of the second housing 40, and is connected to the rearconnection end 9 e.

The second housing 40 includes a second body 41 and a second channelforming member 43. The second body 41 has a cylindrical shape of which afront end and a rear end (both ends) are opened, is coupled to the rearend of the first body 11 of the first housing 10, and is connected tothe diluted gas exhaust pipe 50.

The second channel forming member 43 is disposed in the second body 41.The second channel forming member 43 forms an air diluting part 45 and adiluted gas moving path 47 between an outer surface thereof and an innerperipheral surface of the second body 41.

The air diluting part 45 is to dilute the hydrogen in the exhaust gasintroduced into the exhaust gas moving path 15 of the first housing 10by the external air. A configuration of the air diluting part 45described above will be described in more detail below.

In addition, the diluted gas moving path 47 is a path through which thediluted gas in which the concentration of hydrogen in the exhaust gas isdiluted by the external air in the air diluting part 45 moves to thediluted gas exhaust pipe 50.

The second channel forming member 43 as described above is connected tothe inner peripheral surface of the second body 41 through secondconnection ribs 49 having a radial shape. The number of secondconnection ribs 49 is two or more, for example, eight, and the secondconnection ribs 49 are disposed to be spaced apart from each other by apredetermined interval in an inner peripheral direction of the secondbody 41.

The second connection ribs 49 integrally connect an outer surface of thesecond channel forming member 43 and the inner peripheral surface of thesecond body 41 to each other. Therefore, the air diluting part 45 isconnected to the exhaust gas moving path 15 of the first housing 10through a space between the second connection ribs 49 between the outersurface of the second channel forming member 43 and the inner peripheralsurface of the second body 41. In embodiments, the air diluting part 45is disposed at a front side between the outer surface of the secondchannel forming member 43 and the inner peripheral surface of the secondbody 41 at the coupled portion between the first body 11 and the secondbody 41, and is connected to the exhaust gas moving path 15.

Therefore, the diluted gas moving path 47 is connected to the airdiluting part 45 through the space between the second connection ribs 49between the outer surface of the second channel forming member 43 andthe inner peripheral surface of the second body 41. The diluted gasmoving path 47 is disposed at a rear side between the outer surface ofthe second channel forming member 43 and the inner peripheral surface ofthe second body 41, and is connected to the air diluting part 45. Inembodiments, the diluted gas moving path 47 is formed between a rear endof the second channel forming member 43 and the second body 41.

Meanwhile, the air diluting part 45 forms a mixing zone 46 connected tothe exhaust gas moving path 15 of the first housing 10. The mixing zone46 is a zone in which the exhaust gas introduced through the exhaust gasmoving path 15 and the external air are mixed with each other, is formedat a front side between the outer surface of the second channel formingmember 43 and the inner peripheral surface of the second body 41 at thecoupled portion between the first body 11 and the second body 41.

In order to partition the mixing zone 46, a mixing protrusion 51 isformed at a front end of the second channel forming member 43. Themixing protrusion 51 protrudes from a front end outer peripheral edge ofthe second channel forming member 43 toward the first channel formingmember 13 of the first housing 10. Therefore, the mixing zone 46 isextended toward the coupled portion between the first body 11 and thesecond body 41 between an outer surface of the mixing protrusion 51 andthe inner peripheral surface of the second body 41, and may be connectedto the exhaust gas moving path 15 of the first housing 10.

In addition, the second channel forming member 43 has a second gasinducing surface 53 formed at a rear end thereof, the second gasinducing surface 53 having a conical shape such as a taper shapeprotruding rearward. The second gas inducing surface 53 serves to inducethe diluted gas introduced from the air diluting part 45 into thediluted gas moving path 47 to the diluted gas exhaust pipe 50.

In addition, the second channel forming member 43 has a second mountinggroove 55 formed at a front end thereof. The second mounting groove 55is formed rearward at the front end of the second channel forming member43. The second mounting groove 55 faces the first mounting groove 21 ofthe first channel forming member 13, and is coaxial with an internalcenter of the first mounting groove 21, and is formed at the front endof the second channel forming member 43. The second mounting groove 55is provided as an accommodating groove in which a motor part 70 to bedescribed below is mounted.

The motor part 70 described above, which provides a torque to thepumping part 30, is installed in the second channel forming member 43 ofthe second housing 40. In detail, the motor part 70 is mounted in thesecond mounting groove 55 of the second channel forming member 43.

The motor part 70 includes a shaft 71 rotated at a set speed by anelectrical signal. The motor part 70 is installed to be connected to thepumping part 30 through the shaft 71. Therefore, when the electricalsignal is applied to the motor part 70 to rotate the shaft 71, thepumping part 30 is rotated in the first mounting groove 21 of the firsthousing 10, and may suck the external air through the air inlet 23 ofthe first housing 10.

Therefore, the motor part 70 is mounted in the second mounting groove 55of the second channel forming member 43 through a mounting bracket 73 soas to be spaced apart from an inner peripheral surface of the secondmounting groove 55 by a predetermined gap. In this case, the gap betweenthe inner peripheral surface of the second mounting groove 55 and themotor part 70 may be sealed through a predetermined sealing means suchas a mechanical seal.

Meanwhile, in an embodiment of the present invention, the second housing40 includes a coolant moving path 61 allowing a coolant as a coolingmedium to move therethrough and cooling heat generated in the motor part70. The coolant moving path 61 includes coolant moving grooves 63, acoolant inlet 65, and a coolant outlet 67.

The coolant moving grooves 63 are formed in the second connection ribs49 in the second housing 40, and are connected to the second mountinggroove 55 of the second channel forming member 43. The coolant movinggrooves 63 are connected to the gap between the inner peripheral surfaceof the second mounting groove 55 and the motor part 70.

The coolant inlet 65 is to introduce the coolant supplied through acoolant supplying means into the coolant moving grooves 63 and the gapbetween the inner peripheral surface of the second mounting groove 55and the motor part 70. The coolant inlet 65 is formed in the second body41 of the second housing 40, and penetrates through and is connected tothe coolant moving groove 63 of any one of the second connection ribs49.

As described above, the coolant is introduced into the coolant movinggrooves 63 and the gap between the inner peripheral surface of thesecond mounting groove 55 and the motor part 70 through the coolantinlet 65 to cool the heat generated in the motor part 70. Therefore, thesecond connection ribs 49 of the second housing 40 serve as cooling finsradiating the heat.

In addition, the coolant outlet 67 is to discharge the coolantintroduced into the coolant moving grooves 63 and the gap between theinner peripheral surface of the second mounting groove 55 and the motorpart 70 and warmed while cooling the motor part 70. The coolant outlet67 is formed in the second body 41, and penetrates through and isconnected to the coolant moving groove 63 of the other of the secondconnection ribs 49.

In an embodiment of the present invention, the nozzle member or dilutionair supplier 90 is installed at the shaft 71 of the motor part 70between the pumping part 30 and the motor part 70. The nozzle member 90sprays air sucked (introduced) through the air inlet 23 by the pumpingpart 30 while being rotated together with the shaft 71.

The nozzle member 90 is installed at the shaft 71 of the motor part 70so as to be coaxial with the pumping part 30. The nozzle member 90includes a nozzle body 91 having a disk shape having an outer ring partformed at an edge portion thereof, as shown in FIG. 7. The nozzle member90 is a slinger nozzle including a spraying groove 93 formed at an innerside of the outer ring part in the nozzle body 91 and a plurality ofnozzle holes 95 penetrating through the spraying groove 93.

Here, the nozzle holes 95, which are fine holes formed to penetratethrough the spraying groove 93 toward the air diluting part 45, areformed to be spaced apart from each other by predetermined intervals inan outer ring direction along the spraying groove 93. Since the numberand diameters of nozzle holes 95 may be changed depending on drivingspecifications of the fuel cell system, they are not limited to anyspecific value in an embodiment of the present invention.

Hereinafter, an action of the device 100 for decreasing a concentrationof hydrogen exhausted from a fuel cell according to an embodiment of thepresent invention configured as described above will be described indetail with reference to the above drawings and the accompanyingdrawings.

FIG. 8 is a view for describing an operation of the device fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to an embodiment of the present invention.

First, referring to FIG. 1, in an embodiment of the present invention,the fuel cell system 1 exhausts the hydrogen due to the cross-overtogether with the air from the cathodes 2 a of the fuel cells 2 c andexhausts the purge hydrogen from the anodes 2 b of the fuel cells 2 c,when the vehicle is started.

In addition, the fuel cell system 1 exhausts the purge hydrogen from theanodes 2 b of the fuel cells 2 c when the vehicle is driven, andexhausts the hydrogen due to the cross-over together with the air fromthe cathodes 2 a of the fuel cells 2 c when the vehicle is stopped or isin the idle condition (for example, the ISG condition).

The hydrogen exhausted from the fuel cells 2 in the vehicle condition asdescribed above is supplied to the humidifier 5, and is exhaustedtogether the air from the humidifier 5, and the exhaust gas containingthe hydrogen and the air is exhausted through the exhaust line 9 a ofthe exhaust system 9.

In a process of exhausting the exhaust gas through the exhaust line 9 aas described above, in an embodiment of the present invention, anelectrical operation signal is applied to the motor part 70 through acontroller, as shown in FIG. 8. In this case, the motor part 70 rotatesthe pumping part 30 and the nozzle member 90 through the shaft 71.

In this process, the exhaust gas exhausted through the exhaust line 9 ais introduced into the exhaust gas introduction pipe 20, and isintroduced into the exhaust gas moving path 15 of the first housing 10through the exhaust gas introduction pipe 20. In this case, the firstgas inducing surface 19 of the first channel forming member 13 inducesthe exhaust gas into the exhaust gas moving path 15.

The exhaust gas moving along the exhaust gas moving path 15 of the firsthousing 10 is introduced into the air diluting part 45 of the secondhousing 40, and is introduced into the mixing zone 46 extended towardthe coupled portion between the first body 11 and the second body 41between the mixing protrusion 51 of the second channel forming member 43and the inner peripheral surface of the second body 41 and connected tothe exhaust gas moving path 15.

Meanwhile, in a process of introducing the exhaust gas into the mixingzone 46 of the air diluting part 45, in an embodiment of the presentinvention, the pumping part 30 is rotated by the motor part 70 asdescribed above, and sucks the external air into an inner portionbetween the first and second housings 10 and 40 through the air inlet 23of the first housing 10.

In this process, in an embodiment of the present invention, the nozzlemember 90 is rotated by the motor part 70 as described above, and spraysthe air sucked by the pumping part 30 to the mixing zone 46 of the airdiluting part 45.

Here, the nozzle body 91 of the nozzle member 90 is rotated at a highspeed by the motor part 70, and the air moves to the spraying groove 93of the nozzle body 91 by centrifugal force and is sprayed at a highspeed through the nozzle holes of the spraying groove 93.

As described above, the external air is sprayed to the mixing zone 46through the nozzle member 90 simultaneously with introducing the exhaustgas into the mixing zone 46 of the air diluting part 45. Therefore, inan embodiment of the present invention, the exhaust gas and the air aremixed with each other in the mixing zone 46 to dilute the hydrogen inthe exhaust gas by the external air, thereby making it possible todecrease a concentration of hydrogen.

In addition, in a state in which the hydrogen in the exhaust gas isdiluted by the external air in the air diluting part 45, in anembodiment of the present invention, the diluted gas moves along thediluted gas moving path 47 of the second housing 40, and is exhaustedinto the atmosphere through the diluted gas exhaust pipe 50. In thiscase, the second gas inducing surface 53 of the second channel formingmember 43 induces the diluted gas moving along the diluted gas movingpath 47 to the diluted gas exhaust pipe 50 including an outlet.

On the other hand, in a process of diluting the hydrogen in the exhaustgas by the external air as described above, heat is generated in themotor part 70. Therefore, in an embodiment of the present invention, thecoolant is injected into the coolant inlet 65 of the second housing 40through the cooling supplying means.

Therefore, the coolant is introduced into the coolant moving grooves 63in the second connection ribs 49 and the gap between the innerperipheral surface of the second mounting groove 55 and the motor part70 through the coolant inlet 65, and cools the heat generated in themotor part 70. In this case, the heat generated in the motor part 70 iscooled by the coolant, and is discharged to the outside through thesecond connection ribs 49.

In addition, the coolant introduced into the coolant moving grooves 63and the gap between the inner peripheral surface of the second mountinggroove 55 and the motor part 70 and warmed while cooling the motor part70 is discharged through the coolant outlet 67.

According to the device 100 for decreasing a concentration of hydrogenexhausted from a fuel cell according to an embodiment of the presentinvention configured as described above, the hydrogen in the exhaust gasexhausted from the humidifier 5 through the exhaust line 9 a of theexhaust system 9 may be diluted by the external air introduced through apumping structure and a nozzle spraying structure.

Therefore, in an embodiment of the present invention, the concentrationof hydrogen exhausted into the atmosphere through the exhaust system 9of the fuel cell system 1 is effectively decreased, thereby making itpossible to satisfy fuel cell vehicle exhaust hydrogen restrictionrelated regulations of Korea and global technical regulations (GTR) andsecure a competitive advantage in terms of a decrease in hydrogenexhausted from the fuel cell vehicle.

FIG. 9 is a view showing a modified example of the nozzle member used inthe device for decreasing a concentration of hydrogen exhausted from afuel cell according to an embodiment of the present invention.

Referring to FIG. 9, a modified example of the nozzle member 190according to an embodiment of the present invention may be formed in animpeller type, unlike the nozzle member including the fine nozzle holesas described above.

For example, the nozzle member or dilution air blower 190 has astructure in which a plurality of impeller wings 193 having a curvedsurface are disposed between first and second disks 191 and 192 and anair introduction hole 195 is formed in the first disk 191.

Here, the second disk 192 of the nozzle member 190 is coupled to theshaft of the motor part, and the air introduction hole 195 is connectedbetween the impeller wings 193. An air introduction end 194 aintroducing air through the air introduction hole 195 and an air exhaustend 194 b exhausting the air are formed between the impeller wings 193.

In this case, the impeller wings 193 have a shape in which they are benttoward edges of the first and second disks 191 and 192 on the basis ofthe air introduction hole 195. Further, the impeller wings 193 have ashape in which an air moving cross-sectional area therebetween graduallybecomes large from the air introduction end 194 a toward the air exhaustend 194 b.

Therefore, the nozzle member 190 according to embodiments of the presentmodified example is rotated by the motor part, and introduces theexternal air sucked by the pumping part into the air introduction end194 a of the impeller wings 193 through the air introduction hole 195.The air introduced into the air introduction end 194 a is exhaustedthrough the air exhaust end 194 b, and may be introduced into the airdiluting part.

Therefore, in the present modified example, a relatively large flow rateof external air is sprayed to the air diluting part through the nozzlemember 190 formed in the impeller type, thereby making it possible tofurther improve mixing performance between the exhaust gas and theexternal air.

FIG. 10 is a view showing a modified example of the device fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to an embodiment of the present invention.

Referring to FIG. 10, a modified example of the device for decreasing aconcentration of hydrogen exhausted from a fuel cell according to anembodiment of the present invention may include a bypass pipeline 80connecting the front end of the exhaust gas moving path 15 of the firsthousing 10 and the air diluting part 45 to each other.

In detail, the bypass pipeline 80 connects the air diluting part 45 andthe exhaust gas introduction pipe 20 between the first and secondhousings 10 and 40 to each other. To this end, a first connection hole81 connected to the air diluting part 45 is substantially formed in thefirst housing 10. In addition, a second connection hole 82 connected tothe first connection hole 81 through the bypass pipeline 80 is formed inthe exhaust gas introduction pipe 20.

Therefore, in the present modified example, in a process of mixing theexhaust gas and the external air with each other in the air dilutingpart 45, a flow velocity of the exhaust gas at the front end of theexhaust gas moving path 15 is increased by the first gas inducingsurface 19 of the first channel forming member 13, such that a pressureat the front end of the exhaust gas moving path 15 is decreased.

In this case, in the present modified example, some of the exhaust gasand the external air in the air diluting part 45 may be bypassed to thefront end of the exhaust gas moving path 15 through the bypass pipeline80 by a pressure difference between the air diluting part 45 having arelatively high pressure and the front end of the exhaust gas movingpath 15 having a relatively low pressure.

Therefore, in the present modified example, the exhaust gas may bere-circulated from the air diluting part 45 to the front end of theexhaust gas moving path 15. Accordingly, a time in which the exhaust gasis introduced into the air diluting part 45 through the exhaust gasmoving path 15 is delayed, thereby making it possible to further improvedilution performance of the hydrogen in the exhaust gas by the externalair.

FIG. 11 is a view showing a device for decreasing a concentration ofhydrogen exhausted from a fuel cell according to another embodiment ofthe present invention.

Referring to FIG. 11, the device 200 for decreasing a concentration ofhydrogen exhausted from a fuel cell according to another embodiment ofthe present invention has a structure in which it may primarily decreasea concentration of hydrogen in exhaust gas by external air andsecondarily decrease the concentration of hydrogen in the exhaust gas bya catalyst reaction.

In embodiments, in another embodiment of the present invention, thedevice 200 for decreasing a concentration of hydrogen exhausted from afuel cell that may dilute a relatively high concentration of hydrogenincluded in the exhaust gas by the external air and the catalystreaction in a low flow rate/low pressure condition in which a low flowrate of exhaust gas is exhausted through the exhaust line 9 a when thevehicle is started and is stopped or is in the idle condition isprovided.

To this end, the device 200 for decreasing a concentration of hydrogenexhausted from a fuel cell according to another embodiment of thepresent invention basically has the structure according to theembodiment described above, and includes a catalyst diluting part 280disposed in the diluted gas moving path 47 of the second housing 40.Hereinafter, components that are the same as those of the embodimentdescribed above will be denoted by the same reference numerals, and adescription therefor will be omitted.

In another embodiment of the present invention, the catalyst dilutingpart 280 is to dilute hydrogen in the diluted gas in which aconcentration of hydrogen is diluted by the external air in the airdiluting part 45 by the catalyst reaction. The catalyst diluting part280 is disposed in the diluted gas moving path 47 of the second housing40.

The catalyst diluting part 280 includes a catalyst 281 deposited on aninner wall surface of the diluted gas moving path 47 in the secondhousing 40. The catalyst 281 may be a catalyst layer coated or depositedat a set thickness on the inner peripheral surface of the second body41, the outer surface of the second channel forming member 43, and outersurfaces of the second connection ribs 49 in the diluted gas moving path47.

The catalyst 281 reacts to hydrogen and oxygen in the diluted gas movingalong the diluted gas moving path 47 to generate heat and water, therebyserving to decrease the concentration of hydrogen. The catalyst 281separates the hydrogen in the diluted gas into protons and electrons,and allows the separated protons and electrons to react to oxygen in theair, thereby generating an exothermic reaction generating the heat andthe water is performed.

Since the catalyst 281, in embodiments, can be a catalyst such as metalhydride according to the related art adsorbing the hydrogen to generatethe exothermic reaction and generate the heat and the water, a detaileddescription therefor will be omitted in the present specification.

Therefore, in another embodiment of the present invention, the dilutedgas moves along the diluted gas moving path 47 of the second housing 40in a state in which the hydrogen in the exhaust gas is diluted by theexternal air in the air diluting part 45 to primarily decrease theconcentration of hydrogen, as in the embodiment described above.

In this case, in a process of moving the diluted gas along the dilutedgas moving path 47, the catalyst 281 of the catalyst diluting part 280separates the hydrogen in the diluted gas into the protons and theelectrons and generates the water and the heat by the exothermicreaction between the separated protons and electrons and the oxygen inthe air. In another embodiment of the present invention, since thehydrogen in the diluted gas reacts to the catalyst 281 while the dilutedgas is uniformly dispersed along the diluted gas moving path 47,explosion sound and explosion pressure due to the catalyst reaction maybe prevented.

Therefore, in another embodiment of the present invention, the hydrogenand the oxygen in the diluted gas are converted into water by thecatalyst reaction of the catalyst 281, such that the hydrogen isdiluted, thereby making it possible to secondarily decrease theconcentration of hydrogen contained in the diluted gas. In a state inwhich the concentration of hydrogen in the diluted gas is secondarilydecreased through the catalyst diluting part 280, the diluted gas isexhausted through the diluted gas exhaust pipe 50.

In another embodiment of the present invention described above, theconcentration of hydrogen exhausted into the atmosphere may beeffectively decreased by diluting the relatively high concentration ofhydrogen included in the exhaust gas by the external air and thecatalyst reaction in the low flow rate/low pressure condition in whichthe low flow rate of exhaust gas is exhausted through the exhaust line 9a when the vehicle is started and is stopped or is in the idlecondition.

Meanwhile, in another embodiment of the present invention, the heat isgenerated in a process in which the hydrogen in the diluted gas reactsto the catalyst 281. This heat may be discharged to the outside bymoving the coolant through the coolant moving path 61.

On the other hand, in another embodiment of the present invention, invarious failure modes in which a high concentration of hydrogen iscontinuously exhausted, such as damage to the fuel cell stack, collisionof the vehicle, a mode in which dilution by the air is not performed,and the like, heat may be rapidly generated by a reaction between thehigh concentration of hydrogen and the catalyst 281.

Therefore, the device 200 for decreasing a concentration of hydrogenexhausted from a fuel cell according to another embodiment of thepresent invention further includes a safety means forcibly exhaustingthe coolant moving along the coolant moving path 61 to the diluted gasmoving path 47 to prevent an excessive rise in a temperature and a riskof a fire due to the reaction between the high concentration of hydrogenand the catalyst 281.

In another embodiment of the present invention, the safety meansincludes a coolant forcible exhaust hole 268 connecting the coolantmoving path 61 and the diluted gas moving path 47 to each other and acap 269 installed in the coolant forcible exhaust hole 268.

The coolant forcible exhaust hole 268 is formed in at least one of thesecond connection ribs 49 of the second housing 40, and is connected tothe coolant moving groove 63 of the second connection rib 49. Inembodiments, the coolant forcible exhaust hole 268 connects the coolantmoving groove 63 of the second connection rib 49 and the diluted gasmoving path 47 to each other.

In addition, the cap 269, which is fitted into the coolant forcibleexhaust hole 268 and closes the coolant forcible exhaust hole 268, andis formed of a polymer material that may be destroyed at a settemperature (a high temperature).

Therefore, in the case in which the heat is rapidly generated due to thereaction between the high concentration of hydrogen and the catalyst 281in the various failure modes in which the high concentration of hydrogenis continuously exhausted, the cap 269 formed of the polymer materialopens the coolant forcible exhaust hole 268 while being destroyed by theheat in another embodiment of the present invention.

Therefore, the coolant moving along the coolant moving path 61discharges the heat depending on the reaction between the highconcentration of hydrogen and the catalyst 281 to the outside whilebeing exhausted to the diluted gas moving path 47 through the coolantforcible exhaust hole 268.

Therefore, in another embodiment of the present invention, the excessiverise in the temperature and the risk of the fire due to the reactionbetween the high concentration of hydrogen and the catalyst 281 in thevarious failure modes in which the high concentration of hydrogen iscontinuously exhausted may be prevented.

FIG. 12 is a view showing a modified example of the device fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to another embodiment of the present invention.

Referring to FIG. 12, in the modified example of the device 200 fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to another embodiment of the present invention, a catalystdiluting part 380 may include a catalyst 381 having a plurality oflattice holes 383 formed to move the diluted gas and buried in thediluted gas moving path 47 in the second housing 40.

In the present modified example, the catalyst 381 is formed bysupporting a catalyst material on a carrier, and the lattice holes 383moving the diluted gas are formed in the carrier. The lattice holes 383are arranged along the diluted gas moving path 47, and may be formed ina quadrangular lattice shape, a hexagonal lattice shape, or a triangularlattice shape. In addition, the catalyst material may include platinumand palladium.

The shapes of the lattice holes 383 of the catalyst 381 as describedabove are variously changed, thereby making it possible to decrease anamount of used catalyst material and maximize catalyst dilution reactionefficiency of the hydrogen in the present modified example.

Since the catalyst 381 is a catalyst such as metal hydride according tothe related art adsorbing the hydrogen to generate the exothermicreaction and generate the heat and the water, a detailed descriptiontherefor will be omitted in the present specification.

Here, the catalyst 381 may be formed so that cross-sectional areas ofthe lattice holes 383 gradually become small in a moving direction ofthe diluted gas, as shown in FIGS. 13A and 13B. In embodiments, thelattice holes 383 are formed so that moving cross-sectional areas of thediluted gas gradually become small from the front of the diluted gasmoving path 47 into which the diluted gas is introduced toward the rearof the diluted gas moving path 47.

Therefore, in the present modified example, a reaction area between thehydrogen in the diluted gas and the catalyst material is increased bythe lattice holes 383 as described above, thereby making it possible tofurther improve reaction efficiency and hydrogen concentrationdecreasing performance of the catalyst 381 and minimize differentialpressure loss depending on movement of the gas.

Since the other components and acting effects of the device 200 fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to another embodiment of the present invention as describedabove are the same as those of the embodiment described above, adetailed description therefor will be omitted.

FIG. 14 is a view showing a device for decreasing a concentration ofhydrogen exhausted from a fuel cell according to yet another embodimentof the present invention.

Referring to FIG. 14, the device 300 for diluting hydrogen in exhaustgas or decreasing a concentration of hydrogen exhausted from a fuel cellaccording to yet another embodiment of the present invention has astructure in which it does not require a vacuum pumping means forsucking the external air, unlike the embodiments described above.

Since a first housing 10, a second housing 40, a motor part 70, and anozzle member 90 of the device 300 for decreasing a concentration ofhydrogen exhausted from a fuel cell are the same as those of theembodiments described above, a description therefor will be omitted.

The device 300 for decreasing a concentration of hydrogen exhausted froma fuel cell according to the yet another embodiment of the presentinvention includes a connection line 405 connecting an air compressor401 and the air inlet 23 of the first housing 10 to each other as theair supplying unit 3 (see FIG. 1) described above in order to remove thevacuum pumping means as in the embodiments described above.

Here, the air compressor 401 sucks and compresses the external air anddischarges the compressed external air to the humidifier 5 (see FIG. 1),and a breathing hole 403 exhausting the air at the time ofsucking/compressing and discharging the air is formed at a rear end ofthe air compressor 401. Since the configuration of the air compressor401 described above is well known to a person of an ordinary skill inthe art, a detailed description therefor will be omitted in the presentspecification.

The connection line 405 connects the breathing hole 403 of the aircompressor 401 and the air inlet 23 to each other and supplies the airexhausted through the breathing hole 403 to the air inlet 23, in yetanother embodiment of the present invention.

Therefore, in yet another embodiment of the present invention, the airexhausted through the breathing hole 403 of the air compressor 401 isintroduced into the air inlet 23 through the connection line 405,thereby making it possible to dilute the hydrogen in the exhaust gas bythe external air by a simple configuration without including the vacuumpumping means such the rotary vane for pumping the external air.

Since the other components and acting effects of the device 300 fordecreasing a concentration of hydrogen exhausted from a fuel cellaccording to yet another embodiment of the present invention asdescribed above are the same as those of the embodiments describedabove, a detailed description therefor will be omitted.

In embodiments, referring to FIGS. 1-14, an apparatus 100 for reducing aconcentration of hydrogen in exhaust gas from a fuel cell 2 in avehicle. The apparatus 100 is connected to an exhaust gas pipe 9. In oneembodiment, the apparatus 100 is mounted between two consecutive exhaustpipe. The apparatus 100 includes an exhaust inlet for receiving exhaustgas and an exhaust outlet for discharging the exhaust gas and a housingincluding a housing wall defining an inner space between the exhaustinlet and the exhaust outlet. The inner space includes a central regionand a peripheral region surrounding the central region. The apparatus100 further includes an exhaust flow guide 13 located in the centralregion of the inner space and including a guide surface 19 spaced fromthe housing wall such that the exhaust gas received through the inlet isguided by the guide surface 19 to flow through the peripheral region ofthe inner space. The apparatus 100 includes a dilution air supplier 90,190 located in the central region of the inner space and downstream theexhaust flow guide 13. The dilution air supplier receives dilution airfrom outside the housing and forcibly supply the dilution air toward theperipheral region in which the exhaust gas flows such that the dilutionair is mixed with the exhaust gas flowing the peripheral region of theinner space, thereby reducing the concentration of hydrogen in theexhaust gas.

In embodiments, the apparatus 100 further includes an additional exhaustflow guide 43 to guide the exhaust gas flowing the peripheral regiontoward the outlet. The dilution air supplier 90, 190 is located betweenthe exhaust flow guide 13 and the additional exhaust flow guide 43. Thedilution air supplier 90, 190 includes two circular walls spaced fromeach other for providing a channel therebetween. Air can flow in aradial direction from the central portion to the periphery of thedilution air supplier. One of the circular walls has a hole at itscentral area for receiving dilution air supplied from outside thehousing. In one embodiment, the dilution air flows generally in a radialdirection and injected through holes 95 formed on and angularly arrangedthroughout a circumferential wall of the supplier 90 as shown in FIG. 7.The supplier rotates about a central axis for effective mixing ofdilution air and the exhaust. In another embodiment, as shown in FIG. 9,fans are formed between and fixed to the two circular walls, and theperiphery of the supplier is completely open such that dilution air isblown toward the peripheral region of the inner space when the supplier190 rotates about a central axis.

While this invention has been described in connection with what ispresently considered to be practical example embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

<Description of symbols> 1 fuel cell system 2 fuel cell stack 2a cathode2b anode 2c fuel cell 3 air supplying unit 4 hydrogen supplying unit 5humidifier 6 hydrogen re-circulating unit 7 heat/water managing unit 8purge valve 9 exhaust system 9a exhaust line 9b one portion 9c the otherportion 9d front connection end 9e rear connection end 10 first housing11 first body 13 first channel forming member 15 exhaust gas moving path17 first connection rib 19 first gas inducing surface 20 exhaust gasintroduction pipe 21 first mounting groove 23 air inlet 30 pumping part40 second housing 41 second body 43 second channel forming member 45 airdiluting part 46 mixing zone 47 diluted gas moving path 49 secondconnection rib 50 diluted gas exhaust pipe 51 mixing protrusion 53second gas inducing surface 55 second mounting groove 61 coolant movingpath 63 coolant moving groove 65 coolant inlet 67 coolant outlet 70motor part 71 shaft 73 mounting bracket 80 bypass pipeline 81 firstconnection hole 82 second connection hole 90, 190 nozzle member 91nozzle body 93 spraying groove 95 nozzle hole 191, 192 disk 193 impellerwing 194a air introduction end 194b air exhaust end 195 air introductionhole 280, 380 catalyst diluting part 281, 381 catalyst 268 coolantforcible exhaust hole 269 cap 383 lattice hole 401 air compressor 403breathing hole 405 connection line

What is claimed is:
 1. A device for decreasing a concentration ofhydrogen exhausted from a fuel cell, configured in an exhaust system ofa fuel cell system exhausting exhaust gas containing hydrogen and airexhausted from the fuel cell into the atmosphere through an exhaustline, the device comprising: a first housing connected to the exhaustline and having an exhaust gas moving path and an air inlet formedtherein; a pumping part installed in the first housing and sucking airthrough the air inlet; a second housing coupled to the first housing andhaving an air diluting part and a diluted gas moving path formedtherein, the air diluting part being connected to the exhaust gas movingpath and the diluted gas moving path being connected to the air dilutingpart; a motor part installed in the second housing so as to be connectedto the pumping part; a nozzle member installed at a shaft of the motorpart between the motor part and the pumping part, and spraying the airintroduced into the air inlet to the air diluting part while beingrotated by the shaft; and a catalyst diluting part disposed in thediluted gas moving path of the second housing and diluting hydrogen indiluted gas in which a concentration of hydrogen is diluted by air inthe air diluting part by a catalyst reaction.
 2. The device fordecreasing a concentration of hydrogen exhausted from a fuel cell ofclaim 1, wherein: a catalyst is deposited on an inner wall surface ofthe diluted gas moving path in the second housing.
 3. The device fordecreasing a concentration of hydrogen exhausted from a fuel cell ofclaim 1, wherein: a catalyst has a plurality of lattice holes formed tomove the diluted gas, and is buried in the diluted gas moving path inthe second housing.
 4. The device for decreasing a concentration ofhydrogen exhausted from a fuel cell of claim 3, wherein: the latticeholes are formed so that cross-sectional areas thereof gradually becomesmall in a moving direction of the diluted gas.
 5. The device fordecreasing a concentration of hydrogen exhausted from a fuel cell ofclaim 1, wherein: in the second housing, a coolant moving path moving acoolant in order to cool the motor part is formed, a coolant forcibleexhaust hole connecting the coolant moving path and the diluted gasmoving path to each other is formed, and a cap formed of a polymermaterial destroyed at a set temperature is installed in the coolantforcible exhaust hole.